Intermittent drive mechanism



Feb. 5, 1952 H. D'A cosTA 2,584,558

INTERMITTENT DRIVE MECHANISM Filed June 27, 1950 Patented Feb. 5, 1952 Harry da Costa, S naresbrook,. England,-Iassignor to The Plessey Company Limited, Ilford,- England, a British company ApplicatiomJnne-M,1950, Serial No. 170,507

I Great Britain June 30,1949 I acl im (01.:14-437) "arms; invention. relates -to intermittentiidrlve mechanism.

An object of the inventionis =to1provide asimple and fficientmechanism whichcan be manufactured very cheaply for use in cases where an intermittent drive is required to perform a mechanical operation.

According to this invention a cam gear is intermittently connected to a driving gear through an idle pinion which is supported upon a displaceable member, and a trip mechanism is operatively connected to said member for holding the idle pinion out of mesh with the driving gear when the cam gear has completed an evolution.

Preferably, a fixed abutment is provided for limiting the movement of the idle gear wheel in one direction to avoid any excessive friction or interlocking of said gear between the cam gear and driven gear. I

If desired, the movable member may be spring loaded to enable the cam gear and idle pinion to remain in constant mesh.

The cam gear may have one or more lobes; the actual number will depend upon the period required for the intermittent drive and the nature of the mechanical operation.

The invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a plan view showing the idle pinion disengaged from the driving gear.

Fig. 2 is a plan showing idle pinion released into engagement with the driving gear, and

Fig. 3 is a similar view showing the position of the pawl and liner when the idle pulley reaches the end of a lobe.

Referring to the drawings:

A toothed wheel denoted generally by numeral I is formed into two lobes 2 and 3 of diiferent lengths. Said toothed wheel I is mounted upon a shaft 4 which in turn is supported upon a base plate 5.

A lever 6 has a slot I at one end to receive a pin 8 fixed to the base plate 5. The opposite end of said lever B is formed with a tooth or step 9 for the purpose hereinafter set forth. A pin I fixed at an intermediate position on one face of the lever 6 rotatably supports a pinion II. Said pinion II is held in constant mesh with the lobated toothed wheel I by means of a helical spring I2 connected at one end to. the shaft 4 and at the opposite end to pin IIl integral with lever 6. A trip mechanism consisting of a pawl I3 pivotally supported at I4 to base plate is connected to a rod I5 which is moved in one direction in opposition to a helical-spring I6 on rod I5 between an abutment I'l fixed to the rod I5 and a bearing support I8 fixed to the base plate ,2 5. .Ehefree end of-thepawl I3 engagesgwith'the toothed endflf of lever i as shown -lilige l.

--A driving. pinion" I 9 fixed to adriving: shaft :is so arrangedthat-when the pawl I3 is moved'out of: engagement with the toothed end :9 *ofrlever tthe' pinion I Irotates' on the lobatedgear wheel I into engagement with the driving pinion I9 as shown in Fig. 2, under the influence of the tensioned helical spring I2. Simultaneously, the lever 6 also moves; the amount of movement of lever 6 is arrested by means of a stop fixed to the base plate 5 againstwhich said lever B abuts.

In operation, the normal position of the mechanism is depicted in Fig. l in which the pinion I I is in the idle position and situated at the commencement of one lobe and the trip mechanism is engaged. Assuming the driving pinion is rotating in a clockwise direction, and it is desired to transmit drive over the lobe 2 of wheel I, the rod I5 is pulled to the left either manually or automatically to release the pawl I3 from tooth 9, when the tension of spring I2 causes pinion II to ride on the lobe 2 into engagement with the driving pinion I9 as the lever B is free to move about the pin and slot connection. A drive in an anti-clockwise direction is transmitted to the toothed wheel until the pinion II falls off the lobe 2 on to lobe 3 when the pinion II is disengaged from the driving gear I9 by reason of the fact that as the idle pinion II approaches the end of the lobe 2 the tip of lever 6 is raised above the end of the pawl I3 whereby the tension of spring It causes the pawl I3 to drop into the toothed section 9 of lever 6 thus causing disengagement of the idle pinion II from drivin gear I9, when it is in position for the next cycle; in this instant the amount of rotation imparted to lobe 3' will be greater than lobe 2.

From the foregoing description it will be readily appreciated how an intermittent drive can be transmitted to the shaft 4.

I claim:

1. In an intermittent drive mechanism, a base plate, a cam gear formed with at least two lobes rotatably mounted upon said base plate, a driving pinion carried by the base plate in ofi-set relation to said cam gear, a spring loaded displaceable trip lever mounted on the base plate, a jockey pinion carried by said lever in constant engagement with the cam gear, and a latch member fitted to the base plate operatively connected to the trip lever whereby said jockey pinion engages with the driving pinion when said latch member is disengaged from the trip lever.

2. In an intermittent drive mechanism, a base plate, a cam gear formed with at least two lobes rotatably mounted upon said base plate, a driving pinion carried by the base plate in off-set relation to said cam gear, a spring loaded displaceable trip lever mounted on the base plate, a jockey pinion carried by said lever in constant engagement with the cam gear, a latch member fitted to the base plate operatively connected to the trip lever whereby said jockey pinion engages with the driving pinion when said latch member is disengaged from the trip lever, and a stop means fixed to the base plate limiting the movement of said trip lever in one direction in opposition to its spring loading to prevent excessive friction of said jockey pinion with the cam gear and driving pinion respectively.

3. In an intermittent drive mechanism, a base plate, a cam gear formed with at least two lobes rotatably mounted upon said base plate, a driving pinion carried by the base in off-set relation to said cam gear, a spring loaded displaceable lever mounted on the base plate, a jockey pinion carried thereby, said jockey pinion in constant mesh with the cam gear, said latch member has a toothed element, a pawl pivoted to the base engaging with the toothed element in said displaceable lever whereby the jockey pinion is held out of engagement with the driving pinion, a control member connected to the pawl for disengaging same from the displaceable lever thereby permitting the jockey pinion to engage with the driving pinion and a stop pin fixed to the base plate for limiting the movement of the displaceable lever when released to prevent interlocking of the gears.

HARRY DA COSTA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Golber Aug. 19, 1941 

